'untwist' originates from Old English prefix 'un-' combined with the word 'twist'. The prefix 'un-' meant 'not' or 'reverse', and 'twist' referred to a turning or winding.

'twist' comes from Old English and related Germanic roots meaning 'a turning or twining'. In Middle English the verb 'untwisten/untwisten' (un- + twist) appeared as the negative or reversing action of 'twist', and this developed into modern English 'untwist'.

Initially it meant 'to reverse or undo a twist', and over time it has retained that core sense of 'removing or undoing a twist' both in literal and figurative uses.